Blockages are used to 'block' upstream processes controlling entity arrival at the queue.
| Prompt | Valid Entry | Default |
| Queue ID | Queue number or name | - |
| Capacity | Expression truncated to an integer | Infinite |
| Balk label | Module label to which the balked entity is to be sent | Dispose the entity |
| Blockage level | Expression truncated to an integer | None |
| Blockage | ID Blockage number or name | None |
| Prompt | Value |
| Queue ID | 2 |
| Capacity | 15 |
| Balk label | rejectjobs |
| Prompt | Value |
| Queue ID | partbuffer |
| Blockage level | NQ(partbuffer)+NE(process) > 4 |
| Blockage ID | Noroom |